Surgical screws are utilized for various purposes in surgical operations. Surgical screws are utilized for repairing fractures in bones or for attaching a prosthesis to a bone. Surgical screws are also utilized for plates connected with a patient's body either permanently or temporarily after an operation. When using a surgical drill/driver in an operating environment, it is desirable that the drill/driver torque the screw within the patient's body in the safest, most efficient manner possible.
In many facial or cranial operations, a plate is utilized to stabilize two sections of bone after completion of the operation. Prior to the present invention, typically a hole was drilled into the patient's bone with a surgical drill/driver. A self-tapping suigical screw was then torqued into the hole by hand by the surgeon. In an alternate method, a self drilling surgical screw was utilized. The surgeon, buy virtue of their experience and tactile touch, was careful not to over torque the surgical screw. Over torquing the surgical screw could thereby cause a strip out of the threads that were created within the patient's bone mass.
Although hand torquing threaded surgical screws to attach a plate to a patient's bone is efficient, there are certain undesirable conditions that can occur. Hand torquing a surgical screw can provide a less than optimal result due to the inherent wobble in the rotational axis of a screw driver when the screw driver is turned manually. Even in the hands of the most skilled surgeon, some wobble typically occurs. Secondly, strip out of the threads formed in the bone by over torquing the surgical screw is primarily dependent upon the skill of the surgeon. Thirdly, it is desirable to torque the surgical screw and associated plate to the patient's body in a method that additionally requires less effort by the surgeon. Fourthly, it is desirable to complete torquing of the surgical screw to the patient in less time than a manual torquing procedure.
To improve upon the manual operation of torquing a surgical screw into a patient's bone to secure a plate to patient's body, various powered surgical drills/drivers have been developed. Most of the surgical drill/drivers are electrically and preferably battery powered. One of the major advantages of the electrically powered drill/driver is that the axis of torque remains constant during the torquing operation and therefore the wobble inherent in manual operation by the surgeon is eliminated. However, with the mechanized torquing of the surgical screw into the patient's bone, there is a lack of tactile feedback to the surgeon to alert the surgeon that further torquing operation can inadvertently cause a strip out of the threads formed within the bone matter of the patient.
Prior manual bone screw insertion techniques typically require three to five seconds. To reduce the time required, there has been trend to go toward aforementioned mechanical drill/drivers. However, increasing the speed on a mechanical drill/driver increases the chances of an inadvertent strip out of the formed threads in the patient's bone matter. It is desirable to provide a drill/driver and a method of utilizing the same wherein strip out of the threads formed in the patient's bone can be prevented while allowing the drill/driver to operate to connect a surgical screw with a patient within time segments as short as 45 ms (actual screw insertion time varies dependent upon the size of the screw). Additionally, it is also desirable to provide a drill/driver that has a form of bit recognition to allow the surgical drill/driver to override a manual command signal to the drill/driver when the manually commanded signal of the drill/driver is outside a desired operational parameter for the drill bit or driver bit that is connected with the surgical drill/driver.